The focus of this dissertation is to propose analytical models to study the impact of collisions and interference in heterogeneous wireless networks and propose simple scalable and lightweight protocols that use these models to adapt to network conditions thus increasing efficiency, decreasing energy consumption and prolonging network lifetime.

The contributions of this dissertation are multifold and are summarized as follows:

- Analytical models to study the impact of collisions and interference on both broadcast and unicast messages. These analytical models are incorporated into the proposed protocols to adapt to the prevailing network conditions to improve their performance.

- Optimized Flooding Protocol (OFP) a geometric approach to achieve network wide broadcast of messages. The key advantages are - simple and stateless, minimizes the number of retransmissions and more importantly ability to adapt to network conditions to guarantee required reliability criteria. OFP is also extended to 3D networks and the performance is verified through rigorous simulations.

- Adaptive Routing and Energy Management (AREM), an integrated routing and MAC protocol that uses the concept of random wakeup and forwarding set based routing to simultaneously conserve energy and achieve low latencies. Nodes adapt their transmission power to the prevailing network conditions to operate at optimal conditions, thus further improving the network lifetime and reducing latencies.

- Efficient Co-ordination Protocol (ECP) that exploits high node redundancy to elect a small subset of nodes to perform network tasks. The subset of nodes is periodically rotated and each node is active for a duration proportional to its capabilities. The load is uniformly distributed among all nodes.